Electronics & Electrical MCQs

Q:

In a parallel circuit, with a number of resistors, the voltage across each resistor is ________

A) The same for all resistors B) Is divided equally among all resistors
C) Is divided proportionally across all resistors D) Is zero for all resistors
 
Answer & Explanation Answer: A) The same for all resistors

Explanation: In parallel circuits, the current across the circuits vary whereas the voltage remains the same.

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238
Q:

If two bulbs are connected in parallel and one bulb blows out, what happens to the other bulb?

A) The other bulb blows out as well B) The other bulb continues to glow with the same brightness
C) The other bulb glows with increased brightness D) The other bulb stops glowing
 
Answer & Explanation Answer: B) The other bulb continues to glow with the same brightness

Explanation: If one bulb blows out, it acts as an open circuit. Current does not flow in that branch but it continues to flow in the other branch of the parallel circuit. Hence the other bulb continues to glow. Also the voltage across other bulb remains the same due to which power delivered to it remains the same so it continues to glow with the same brightness.

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246
Q:

What happens to the current in the series circuit if the resistance is doubled?

A) It becomes half its original value B) It becomes double its original value
C) It becomes zero D) It becomes infinity
 
Answer & Explanation Answer: A) It becomes half its original value

Explanation: I=V/R. If R becomes 2R then I becomes I/2 i.e. half of its original value.

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782
Q:

What is the voltage measured across a series short?

A) Infinite B) Zero
C) The value of the source voltage D) Null
 
Answer & Explanation Answer: B) Zero

Explanation: A short is just a wire. The potential difference between two points of a wire is zero hence the voltage measured is equal to zero.

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160
Q:

Many resistors connected in series will?

A) Divide the voltage proportionally among all the resistors B) Divide the current proportionally
C) Increase the source voltage in proportion to the values of the resistors D) Reduce the power to zero
 
Answer & Explanation Answer: A) Divide the voltage proportionally among all the resistors

Explanation: In a series circuit, the current remains the same across all resistors hence the voltage divides proportionally among all resistors.

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285
Q:

A voltage across a series resistor circuit is proportional to?

A) The amount of time the circuit was on for B) The value of the resistance itself
C) The value of the other resistances in the circuit D) The power in the circuit
 
Answer & Explanation Answer: B) The value of the resistance itself

Explanation: V=IR hence the voltage across a series resistor circuit is proportional to the value of the resistance.

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262